Macs are connecting through SMB2 (early in 10.9 we had some issues with large files - over a few GB- failing to copy, which forcing CIFS worked around, haven't had to do that since 10.9.3) and getting 100 MB/s+ on transfers (with CIFS forced, it was 50 MB/s maximum)

We are not using dedup feature of Windows Server (I believe our storage level SAN - a 3Par is doing dedup).

And regarding the story "Mavericks ACL bug keeps Windows users locked out" from Monday August 18, 2014: Time Machine in Mavericks doesn't have a setting for locking files like Lion did. I can't remember if it was removed in 10.8 or in 10.9 now. I don't have a 10.8 machine available at the moment to double-check.